1. Field of the Invention
The invention relates to a control device for an internal combustion engine and a hybrid vehicle. More specifically, the invention relates to a control device for an internal combustion engine that is equipped with an in-cylinder fuel injection valve that injects fuel into a cylinder, a port fuel injection valve that injects fuel into an intake port, a purification catalyst that is provided in an exhaust system, and an exhaust gas recirculation device that recirculates exhaust gas of the internal combustion engine to an intake system of the internal combustion engine, and to a hybrid vehicle that is equipped with the control device for the internal combustion engine.
2. Description of Related Art
Conventionally, as this kind of control device for an internal combustion engine, there has been proposed a control device that calculates an adhesion ratio as a ratio of adhesion of fuel injected from an injector to a wall surface of an intake port and a wall surface of an intake valve and a residual ratio as a ratio of port adherent fuel and valve adherent fuel remaining adherent to the wall surface of the intake port and the wall surface of the intake valve, referring to a map, and calculates a fuel injection amount through model calculation using the calculated residual ratio and the calculated adhesion ratio as parameters during base operation in which the target air-fuel ratio is set to a value in the vicinity of a stoichiometric air-fuel ratio (e.g., see Japanese Patent Application Publication No. 2007-187071 (JP-2007-187071 A). If the amount of fuel is increased with the target air-fuel ratio being set different from a value during base operation, this control device calculates a residual ratio and an adhesion ratio at the time of the increase in the amount of fuel referring to a map other than the one used during base operation, and calculates a fuel injection amount through model calculation using the calculated residual ratio and the calculated adhesion ratio as parameters. Thus, the fuel supplied into the cylinder is optimized.
By the way, in a control device for controlling an internal combustion engine that is equipped with an in-cylinder fuel injection valve that injects fuel into a cylinder, a port fuel injection valve that injects fuel into an intake port, and an exhaust gas recirculation device that recirculates exhaust gas of the internal combustion engine to an intake system, the suppression of a deterioration in exhaust emission properties at the time of an increase in the amount of fuel for increasing the amount of injected fuel with a view to adjusting the temperature of an exhaust catalyst has been recognized as a task. In fuel injection control of the internal combustion engine, air-fuel ratio learning as the learning of a fuel injection amount for making the air-fuel ratio approach a theoretical air-fuel ratio is executed to restrain the exhaust emission properties from deteriorating. However, when the amount of fuel is increased, the execution of this air-fuel ratio learning is not suitable. Thus, it has been desired to restrain the exhaust emission properties from deteriorating by executing air-fuel ratio learning at a more suitable timing.